Abstract: A method for manufacturing a golf ball by forming half shell covers using a rubber composition and forming golf ball covers using the half shell covers. The adhesion strength between the bonding surfaces of half shells (durability of golf balls) is improved by keeping the shape of half shells and the thickness of the resulting covers uniform. The adhesion strength between the bonding surfaces of half shells is further increased by using a composition containing a crystalline rubber as the rubber composition for cover; molding the rubber composition at a particular temperature while preserving the shape of the half shells without crosslinking or with only partially crosslinking the rubber component; and forming the half shells into a cover while crosslinking the rubber components.

Abstract: A method for manufacturing a golf ball by forming half shell covers using a rubber composition and forming golf ball covers using the half shell covers. The adhesion strength between the bonding surfaces of half shells (durability of golf balls) is improved by keeping the shape of half shells and the thickness of the resulting covers uniform. The adhesion strength between the bonding surfaces of half shells is further increased by using a composition containing a crystalline rubber as the rubber composition for cover; molding the rubber composition at a particular temperature while preserving the shape of the half shells without crosslinking or with only partially crosslinking the rubber component; and forming the half shells into a cover while crosslinking the rubber components.

Abstract: The present invention provides a multi-piece solid golf ball comprising a core consisting of an inner core and an outer core, and one or more layers of cover, wherein the inner core has a diameter of 30 to 39.5 mm and a center hardness in JIS-C hardness of 55 to 70, and is formed from press molded rubber composition comprising polybutadiene, a co-crosslinking agent, an organic peroxide and a filler, and the JIS-C hardness at a distance of 15 mm from the center point of the inner core is higher than the center hardness by 5 to 20; the outer core has a thickness of 0.3 to 2.0 mm and a surface hardness in JIS-C hardness of 75 to 90, and is formed from press molded rubber composition, and the surface hardness of the outer core is higher than the center hardness of the outer core is higher than the center hardness of the inner core by 10 to 35; and the cover contains thermoplastic resin as a base resin, and the outmost cover layer has a thickness of 1.5 to 2.

Abstract: A golf ball exhibits a high spin and easily comes to a halt even when shot from the rough or when shot in a raining condition. The cover material of the golf ball is based on ionomer resin. The cover material has 5-50 parts by weight of a tackifier such as terpene resins, rosin ester resins or the like blended with respect to 100 parts by weight of the base material.

Abstract: A golf ball which produces high spin rate and accordingly readily stops even when being shot from a rough or in the rain is provided. Such a golf ball is constituted of a core and a cover and the cover has a loss tangent of 0.15 to 0.70 at −10° C. in a temperature distribution curve for dynamic viscoelasticity measured in a tensile mode under conditions of temperature increasing rate of 4° C./min, frequency of 10 Hz and initial strain of 1.0 mm.

Abstract: The present invention provides a colored golf ball having soft and good shot feel at the time of hitting, and having excellent discriminability when used in bad weather or the winter season because of its vivid and deep color tone. The present invention relates to a colored golf ball comprising a core having at least one layer and a cover having at least one layer formed on the core, wherein the outermost layer of the cover contains 3.0 to 7.0 parts by weight of fluorescent pigment and 0.05 to 0.5 parts by weight of titanium dioxide, the cover being coated with one or more layers of clear coating, and the surface of the golf ball having an L*-value of 50 to 80, measured using a color difference meter.

Abstract: The present invention provides a golf ball having excellent durability, sufficient for use in driving ranges while maintaining sufficient flight distance and shot feel for use in playing a round of golf. The golf ball comprises a core and a cover covering the core, wherein the core is composed of a vulcanized molded article of a rubber composition comprising 100 parts by weight of a base rubber containing not less than 80% by weight of a butadiene rubber having not less than 80 molar % of cis-1,4 bond, 10 to 30 parts by weight of calcium carbonate, 18 to 35 parts by weight of zinc acrylate or methacrylate and 0.5 to 2.5 parts by weight of a peroxide, and the cover is made from a resin composition having a flexural modulus of 1,400 to 3,800 kgf/cm2, wherein the total volume of dimples of the cover is from 250 to 400 mm3.

Abstract: A rubber composition suitable for use in grips of articles such as golf clubs, tennis rackets, bicycles and tools, comprising (1) a rubber component containing an ethylene-propylene-diene rubber (EPDM), and (2) 5 to 100 parts by weight of a polyisobutylene having a viscosity average molecular weight of 6,000 to 50,000, which provides grips having good feeling of touch, good non-slipping properties in both fine and rainy weather, and giving a small feeling of impact to mis-shot of golf balls as compared with conventional grips.

Abstract: A multi piece solid golf ball comprising:a core (1),at least one intermediate layer (2) formed on the core (1) anda cover (3) covering the intermediate layer (2) consists essentially of (I) 100 to 10% by weight of a polyurthane thermoplastic elastomer and (ii) o to 90% by weight of an ionomer of ethylene-(meth) acrylic acid copolymer and having a flexural modiolus of 500 to 5,000 Kgf/cm.sup.2, and the cover (3) is formed from an ionomer resin of ethylene-(meth)acrylic copolymer and has a shore D hardness of 50 to 75 and the core (1) has a press deformation of 3.0 to 6.0 mm, the press deformation being obtained by applying an initial load of 10 Kg on the core to measure a deformation of core (Xmm) and then applying a final load of 130 Kg on the core to measure a deformation of core (Ymm), followed by calculating (Y-X)mm, which is the press deformation.

Abstract: Disclosed is a golf ball comprising a core 1 composed of a center 1a and an outer shell 1b, and a cover 2 covering said core 1, wherein a specific gravity of said center 1a is 0.2 to 1. The golf ball has excellent flying distance and satisfies other performances of golf balls.

Abstract: A three-piece solid golf ball which attains a long flight distance with excellent controllability which comprises a core having a two-layer structure of a center and a shell covering the center, and a cover covering the core, whereinthe center has a diameter of 25 to 37 mm, a JIS-C hardness of 60 to 85 at its center point, and a JIS-C hardness difference between the center point and a surface of the center of not more than 4,the shell has a JIS-C surface hardness of 75 to 90, andthe cover has a stiffness modulus of 1,200 to 3,600 kg/cm.sup.2, with; the hardness being measured by a JIS-C type hardness tester.

Abstract: A solid golf ball comprising a core and a cover, wherein the core has a trans structure content in polybutadiene of 10 to 30%. The core is produced by vulcanizing a rubber composition containing a butadiene rubber having cis structure content of not less than 90% before vulcanization, as a base rubber, wherein an amount of trans structure after vulcanization is 10 to 30% and a difference in hardness measured by a JIS-C type hardness tester between the center of the core and each point located from the center to the surface at an interval of 5 mm is not more than 10%.The rubber composition for forming the core comprises a vulcanizing agent, a filler, an organic peroxide and an organophosphorus compound, in addition to the butadiene rubber having cis structure content of not less than 90% before vulcanization.

Abstract: A two-piece golf ball, comprising:a core having a surface hardness of 55 to 75 and a sectional hardness at the location other than the core surface layer of 65 to 88, said hardness value being determined by a JIS-C type hardness tester; anda cover covering said core and having a stiffness of 1,000 to 3,000 kg/cm.sup.2 ;wherein said golf ball exhibits a contact area S between itself and a clubface, when hit with a driver at a head speed of 40 m/second, of 4.3 to 5.0 cm.sup.2, S being determined by the equation:S=.pi.(1/2{(a+b)/2}).sup.2wherein a is a transverse diameter of the contact area and b is a longitudinal diameter of the contact area.

Abstract: The present invention provides a three-piece solid golf ball having both excellent hit feeling and large flying distance. The three-piece solid golf ball comprises a core 1 and a cover 2 covering the core 1, and the core 1 has a two-layer structure comprising a center 1a and an outer shell 1b. The center 1a contains an .alpha.,.beta.-unsaturated carboxylic acid metallic salt in an amount of 13 to 28 parts by weight based on 100 parts by weight of a base rubber and the outer shell 1b contains an .alpha.,.beta.-unsaturated carboxylic acid metallic salt in an amount of 28 to 35 parts by weight based on 100 parts by weight of an base rubber. A surface hardness (measured by JIS-C type hardness tester) of the core 1 is 75 to 88 and a compression deformation amount of the core 1 is 2.7 to 5.0 mm.

Abstract: The present invention provides a one-piece solid golf ball or a two or more piece solid golf ball which comprises an inner core and a cover covering the inner core. The one-piece solid golf ball is formed from a rubber composition which comprises:a base rubber,vulcanized rubber powder, anda vulcanizing agent.The two or more piece solid golf ball comprises an inner core and a cover covering the inner core, the inner core being composed of either one uniform rubber material or a combination of a center and one or more outer layers disposed over the center, wherein one or more rubber portions of the inner core are formed from a rubber composition comprising:a base rubber,vulcanized rubber powder, anda vulcanizing agent.

Abstract: The present invention provides a one-piece solid golf ball or a two or more piece solid golf ball which comprises an inner core and a cover covering the inner core. The one-piece solid golf ball is formed from a rubber composition which comprises:a base rubber,vulcanized rubber powder, anda vulcanizing agent.The two or more piece solid golf ball comprises an inner core and a cover covering the inner core, the inner core being composed of either one uniform rubber material or a combination of a center and one or more outer layers disposed over the center, wherein one or more rubber portions of the inner core are formed from a rubber composition comprising:a base rubber,vulcanized rubber powder, anda vulcanizing agent.

Abstract: The present invention provides a solid golf ball having excellent flying performances, stability upon iron shot and good hit feeling.A solid core 1 comprising an center 1a and an outer shell 1b is coated with a cover 2 to give a three-piece solid golf ball. The center 1a has a diameter of 30.7 to 39.5 mm, a stiffness of 300 to 2,500 kgf/cm.sup.2 and a shore D hardness of 30 to 55. The outer layer core 1b has a thickness of 1.0 to 4.0 mm, a stiffness of 2,500 to 6,000 kgf/cm.sup.2 and a shore D hardness of 55 to 75. The composition of both cores is a butadiene rubber. The cover 2 has a thickness of 0.6 to 2.0 mm, a stiffness of 1,000 to 2,500 kgf/cm.sup.2 and a shore D hardness of 40 to 55. The composition of the cover is an ionomer resin or a mixture of the ionomer resin and a flexible resin.

Abstract: Disclosed is a golf ball having an excellent (soft) hit feeling and excellent durability, which is suitable for use on the driving range. The golf ball has a two-layer structure including a core and a cover for coating the core. A compressive strain of the core is 2.8 to 3.8 mm. A hardness distribution of the core (measured by a JIS-C type hardness tester) is adjusted to 65 to 79 at the center, 70 to 80 at the location which is 5 mm away from the center to the surface, 73 to 80 at the location which is 10 mm away from the center to the surface, 75 to 82 at the location which is 15 mm away from the center to the surface and 70 to 85 at the surface, and a difference in hardness between adjacent locations of the measurement is within 5. The cover contains an ionomer resin as a main material and a stiffness of the cover is 1400 to 3000 kg/cm.sup.2. The golf ball has a ball compression that is 70 to 100 (PGA system).

Abstract: The present invention provides a three-piece solid golf ball having both excellent hit feeling and large flying distance. The three-piece solid golf ball comprises a core 1 and a cover 2 covering the core 1, and the core 1 has a two-layer structure comprising a center 1a and an outer shell 1b. The center 1a contains an &agr;,&bgr;-unsaturated carboxylic acid metallic salt in an amount of 13 to 28 parts by weight based on 100 parts by weight of a base rubber and the outer shell 1b contains an &agr;,&bgr;-unsaturated carboxylic acid metallic salt in an amount of 28 to 35 parts by weight based on 100 parts by weight of an base rubber. A surface hardness (measured by JIS-C type hardness tester) of the core 1 is 75 to 88 and a compression deformation amount of the core 1 is 2.7 to 5.0 mm.

Abstract: Disclosed is a solid golf ball containing at least one rubber portion formed from a rubber composition comprising a base rubber, a co-crosslinking agent and an organic peroxide; an improvement being present in that the base rubber is a mixture of(A) a solid polybutadiene rubber containing cis-1,4 bonds in an amount of at least 40%, and(B) either a liquid polybutadiene rubber or a liquid isoprene-butadiene copolymer rubber, or both.